Regulating choke coil



March 19, 1935. H. A. wl KLINKHAMER 1,994,953

REGULTING CHOKE COIL Filed May 28, 1932 3 Sheets-Sheet 1 a a fa /6 f#.fa

Ml'Ch 19, 1935 H, A. w. KLINKHAMER 1,994,953

REGULATING CHOKE COIL Filed May 28, 1952 3 Sheets-Sheet 2 March 19,1935. H. A. w. KLINKHAMER REGULATING CHOKE COIL Filed May 28, 1932 3Sheets-Sheet 3 Frfy Patented Mar. 19, 1935i UNlTi-:D sTATEs Y 1,994,953aEGuLA'rnvG cnoirncon.

llendrik Abraham Wijnan hoven, Netherlands, assigner to N. V.Gloeilampenfabrieken, Eindhoven,

lands Application May 28,

In Germany d Klinkhamer, Eind- Philipe Nether- 1932, 'sa-m No. 614,216

rune z5, 1931 Claims# (Cl. 171-242) This invention relates to adjustablechoke coils particularly adapted for controlling the current of anon-rotary welding device fed by polyphase current. In connection withsuchdevices itis o known to control or regulate y'the current bymodifying the reactance of a multi-phase choke coil 'which is insertedin the primary circuit of the welding transformer.

In such known devices a continuous control is obtained by providing theViron core of the choke coil with a variable air gap. The great magneticforces produced in said devices cause constructional diflicultiesand toobtain a satisfactory construction is comparatively expensive.

An intermittent regulation may be obtained by the simultaneous andstepwise change of the number of turns of the individual choke-coilphases, by providing these 'phases withl 'a plurality of taps. However,a sufficiently fine adjustment cannot be lobtained with such regulation,unless a large number of taps is provided and a cuordespondinglycomplicated switching device The invention has for its purpose toprovide nmore simple and substantially continuous conv In the controldevice according to the invention the. choke coil winding comprises ineach phase a plurality of taps, the taps being connected (and numbered)in a cyclical order of the phases and in the order of their distancesfrom the starting point of the 'phase winding to a series of contacts ofa switch device by means of which the different.

taps may be connected to the phase supply conductors or to a star pointso as to obtain a series of control' stages. In any of the stages threesuccessively numbered taps' are either connected to the preceding orsucceeding phase supply conductor in order to obtain a polygonconnection or are connected to the starpoint as to obtain afstarconnection. In this manner, the number of stages obtained with a givennumber of taps v is much larger than obtainable with the knownadjustable choke coils, since successive stagesA are obtained by merelyadding or omitting a portion falling betweenrtwo successive taps of asingle winding and furthermore by using the same taps and branches for aseries of control stages obtained with star connection and a' series ofcontrol stages obtained with delta connection. r T'he adjustable chokecoil above referred to may A beof quite small size and of a simple andcheap construction. In one embodiment oftheinvention this is obtained byproviding in 'the switch device three series or rows of contacts, eachhaving an equal number of contacts, the contacts of the middle row beingconnected to the taps of the choke coil, the contacts of one outer rowbeing connected in a cyclical order to the phase supply conductors andthe contacts of the` other outer row being all electricallyinterconnected. The Adiiiferent connections are obtained by connectingeach time a number of successive contacts oithe middle row, which numbercorresponds to that of the phases, to the adjacent contacts of either 10one of the outside rows.

Preferably the contact points of the switch device consist of contactsleeves, while. the connection between these sleeves is eiected by meanslof a contact plug comprising two rows of three, pairwiseinterconnected, pins.

Circuit connections of the type above referred to, do not properly lendthemselves for use with an ordinary multi-phase transformer or with amulti-phase choke coil, since in all or at least in some of the polygonswitch positions the number of turns which the diiierentphases have'inthe circuits is not equal, so that the sum of the magnetic fields of theindividual choke coil cores, does not give zero in these cases. In orderto'nevertheless obtain a compact assembly and a saving in material athree-,phase choke coil v construction may be advantageously used, whichconsists of'three single-phase shell type choke coils of the usual form,`but in which two yokes are omitted and in which one yoke, for instancethe lower, of one of the choke coils serves at the same times as theother, for instance the upper yoke of the succeeding choke coll, and inwhich the coil of the intermediate choke cll is con- Vnected oppositelywith respect to the outer choke coils.

The invention will be more clearly understood by reference to theaccompanying drawings, rep-L resenting, by way of example, oneembodiment 40 thereof. Y l

Fig. 1 is a. circ t diagram of a direct current welding device in whichthe alternating current is rectified by means of gasfilled rectiei'tubes. and in which a choke coil according to the invention is used.

Fig. '2 is a diagrammatic showing of theconnection of the choke-coilwinding for some of the control stages. I-

Fig. 3 is a graphical representation of the 50 welding current asmeasured in the `different positions Vof the contact plug.

. Fig. 4 is a schematic representation of the construction of the ironvcore of an adjustable choke coil according to the invention.

Fig. 5 is a plan view and Fig. 6 is a side view of an adjustable welding'apparatus comprising a regulating choke coil according to theinvention.-

Referring to Fig. 1 the welding transformer 1 may be connected to thenetwork through a switch 2 and a contact plug 3. Ihis also connects tothe network the windings o the regulating choke coil 4, hereafter morefully described. By the insertion of plug 3 a heating transformer 5 isswitched on at the same time. 'I'he secondary side of the weldingtransformer has three windings, which by'means' of center-taps form a 6-phase winding. These windings areconnected at their ends to the anodesof three full-wave rectier tubes 6, '1v and 8,'whose cathodes areconnected across the secondary winding of the heating transformer 5. Themiddle tap of the secondary windingof transformer 5 is connected to aworkpiece 9, and the center taps of the secondary windings of thewelding transformer l. are connectedito a welding electrode 10.

'The regulating choke coil 4 coinprises three phase windings, thestarting points or terminals A1, Ac and A3 o f which may be connected tothe network through the welding current transformer; Each phasewinding'of the regulating choke coil is provided with four taps,including the free ends of the windings. These taps are marked by thereference numerals l1`22 in the order o f their distance from thestarting points or terminals Ai, A'z, and A3 of the respective windings.\Wl1eri going round the three phases always in the same sense the twelvetaps are traversed in the order of the numbering.. Consequently of theoptional three `successive taps there is each time one on-each phase.

A series of ten star-connected-control stagesl is obtained byinterconnecting each time three successively numbered taps so as to forma star point.

obtained by connecting each of three successively numbered taps to thebeginning of the p'e-y cedingv (or succeeding) phase winding.

The positionof the taps may be such that tlie ten star connected controlstages join the ten delta-.connected control stages.

. The upper portion of Fig. l shows how the connections are establishedin the switch arrange- These contact sleeves'justreferred-toconstitutevthe middle series or row ofthi'ee series ofcontact` sleeves. For the sake ofclarityy the connections between thecontact sleeves and the taps are omitted from thef The twelvecontactsleeves -of the upper'v row are connected in groups of three in acyclical order to the starting points A1,'A2 and A3 of the three phasewindings and in such a. manner that opposing contact sleeves. of the tworows are always connected to diierent phases.

All oi the contact sleeves ofjthe lower row are inter-connected and formvthe .star-pointi for star-connection.

These contact sleeves cooperate 'with a contact plug provided with sixpairwiseinter-connected pins. plug isfseparately'shown in-A Fig. 1 anddenoted by-24. This arrangement of the contact sleeves per- A'series often delta-connected control stages l mits the above-referred toconnections to be es tablished in a very simple manner. In order toobtain a star-connection each of three succeeding contact sleeves of theintermediate row is connected by means ot the plug to the correspondingcontact sleeve of the lower row and for obtaining a delta-connectioneach oithem is .connected to the corresponding contact' sleeve of theupper row.

In,the drawings four indicated in dotted lines by way of example. Thesefour positions correspond tothe four connectionI diagrams marked I, H,m, m of Fig. 2 and give corresponding adjustments of the weldingcurrent. i

. l in the position i, the windings of ihcregulting choke coil areconnected in the manner indicated in Fig." 2, on the upper left. Invtbiscase the full phase windings Ai-22, A2-20, iis- 21 are star-connected.The current fed from the welding transformer Lfyiz. the welding current,has its minimum value. l

When the plug is moved to the right in the position marked 1I so as toengage the succeeding positions of the plug are N contact sleeve, thefull phase-winding A2-20 and .i3

A3-21 remain in the circuit, but from the phase-,L h

winding Ai-22 the portion 22-19 is cut out and only the portion Aie-19remains in Ythe circuit; at the top and n the right of Fig. 2 are shownthe circuit connections thus obtained. in this posio tion of the switchapparatus, the current is increased compared with position I.

When through successive displacement of the plug to the right so as toengage successive sleeves been trav- 30 all of the star-connected stageshave ersed, the plug is returned to the left,` but now in the positionto interconnect the sleeves of the upper. and middle rows fordelta-connection. After a number of these stages. have been trav-d'ersed theplug occupies fori instance the position4 XIX, to provide forthe delta-connection shown in Fig. 2 at the bottom on the left. If it isdesired to still further increase the current, the plug is moved furtherto the iight so as to occupy the position XX thus cutting outthe portion11-14 in the corresponding winding of the regulating choke coil. 'I'heconnection thus obtained is shown in Fig. 2 at the bottom on the right.v

This position corresponds tothe last stage and gives the maximum currentstrength obtainable.` 50

stantially a straight line, shows that the percentage of currentincrease with the transition from any stage to the succeeding stage isthe same throughout. C Thus the device makes` it possible to obtain V'twenty diierent stages ,or adjustments inthe welding current strengthand requires only four taps per phase, -including the free end terminalsarithmic Scale. The .fact'that the curve is sub- "0 of the phases. Atthe-same time the maximum 65;

current carried bythe conductors connecting the choke coil-to the switchapparatus and by Y pins and sleevesof the switching apparatus amountsonly to The transitign from one connection to another l 7%."-

ed at the upper and at the lower end by means by the switching apparatusamounts only to times the no-load current of the transformer.

The regulating apparatusis small, simple and cheap and the control intwenty stages allows a practically continuous control. Of course, thenumber of stages may be increased in a simple manner.

In case the taps of the different phase windings are provided at equaldistances from the starting point, in certain stages the differentphases will be symmetrically loaded, while in other stages will beasymmetrically loaded, as appears from Fig. 2. However, the last stagewill be a symmetrical one so that the maximum power of the yweldingapparatus is not decreased by the controldevice.

In one embodiment of the invention the distance between the startingpoints of the windings and the successive taps increase toward the freeend terminals of the phase windings. Such a division has the advajntagethat the maximum load diiference betweenthe individual phases ismaterially smaller than in the case of an equal spacing of the taps.

As has already been stated it is not ad ble\to use the regulatingarrangement referred to with a normal three-phase transformer or athreephase choke coil. In fact, since these haveonly three cores whichare magnetically interconnectof yokes, the sum of the fields is zero.Consequently the sum of the electro-motive forces in-fducedl by theilelds in the three windings is not zero for those connections in whichthe number of turns are unequal. Due to this, unduly large compensatingcurrents would occur in the asymj metrical delta-connections. This alsoholds good for themulti-phase constructions having a phase number otherthan three.

The arrangement according to the invention may be also used if insteadof ya combined m phase core, m separate single phase cores are provided.However, the combined core has `the advantage of a saving in materialsand of greater compactness. This advantage is also partially lost whenthe multi-phase construction is provided with an additional unwound coreby which the yokes are magnetically interconnected. However, theconstruction in which the compensating currentis suppressed has otherdrawbacks.

The same important saving in material obtained with the standardthree-leg construction can, however, also be obtained by means of aconstruction of the multi-phase core as shown in Fig. 4, whichconstruction has several further .practical advantages. l y

'I'he device illustrated may be regarded as consisting of an assembly ofthree single-phase shell type cores 25, 26 and 27 in which two yokes areomitted. When denoting the magnetic fleldsof the three cores by Fi, Fn,andF-i, the yokes 28, 29, l 30 and 31 carry the following fields:

tsm, 5m-F1), str1-Fn, ma The fields F1, Fa, and Fa are assumed to bepositive in the directions indicated by arrows in the drawings. Shouldthe three coils vbe wound and connected in the same sense, each of thetwo mid- `diey yokes would" in accordance with the above terms, carry aileld having a value which is proximately times that of the ileld of theend yokes. However, when the coil of the middle winding of the threesingle-phase windings is oppositely connected, insteadv of the usualrelation existing between the core ilelds namely:

When inserting vthe so found value of Fi in the above terms for the yokefields, the latter become lFi; VgFa; -vmz -yFz Fromthisit appearsthatinthiscasethefour yoke ilelds are equal. Consequently the two middleyokes need not be thicker than the terminal yokes. 'Ihus with thisconstruction the amount of material required is practically the same asthat required for the normal combined three-phase construction.Furthermore the above arrangement has the following advantages:

1. The mutual inductance due to the leakage elds are practically zero.Consequently, the troublesome effect due to unequal mutual inductancesis absent, whereas this is quite pronotmced in the case of a standardthree-legged choke coil and results in unequal loading of the rectifyingvalves, which drawback also manifests itself even when the number ofturns on each of the three cores is the same.

2. 'lhe air gap of veach choke coll core may be adjusted separatelyfincontradistinction to the three-leg construction, thus making it possibletocompensate for differences which mayA exist for some reasons betweenthe three phases.

3. The same type of stamps and punches may be used as for single-phasechoke coils.

4. Instead of clamping the yokes between angle bars the side cores are'clamped between brass strips. For this purpose the bolt aperturesalready normally provided in the core sheets may be used. When usingcommon strips for the three choke coils they are assembled so as to forma unit. The strips must be provided with oblong apertures so that theair gaps may be adjusted. There is no danger of the brass strips beingheated by Foucault currents as may be the case with angle bars.

5. The core sheets need not be wound into the coils but the coils may beslipped over previously formed-cores.

Figs. 5 and 6 show the arrangement of the regulating choke coil 4 in awelding apparatus comprising wheels.

In Fig. 5 the rectifier tubes 6, 'I and 8 are shown as disposed in aseparate space. Furthermore this figure shows the plate 23 together withthe contact sleeves and the plug 24 in plan view.

Fig. 6 shows vthe switch device arranged centrally above the choke coil4 so that the twelve connecting wires are as short as possible while theassembly remains clear.

The regulating device is mounted on the top .of the casing. thus at areadily accessible and properly illuminated place. A hinged cover may beprovided above this regulating device. I

A ventilator (not shown). may serve for coolingtherectifyingvalves,andmaybeplacedat the bottom ofthe case, whereby it alsocoolsthe choke coil and other parts of the apparatus.

` sulting from the combined construction are not obtained.

WhatI claim iszl. A control device for the control of a'polyphasecurrent comprising an adjustable chokecoil to regulate said current,said choke-coil having a plurality or phase windings, andv each windinghaving a plurality of taps, a conductor -for each phase and connected toone end oi its respective phase winding, a switching device having a.series of contacts, the taps of said windings being connected to saidcontacts in a cyclical order of the phases and in the order of theirdisconductor to obtain a tance from the starting point of theirrespective phase, said switchingdevice comprising means to connectsuccessive taps, one of each phase, to the preceding or succeeding phaseconductor to obtain a :Milligan` connection of said phases.

2. A control device tor the control oi a threephase current comprisingan adjustable choke coil to Aregulate said current, said choke coilhaving three phase windings each having a plurality oi taps, a conductorfor each phase and connected- .to one end ot its. respective phasewinding, ,a

switching device having a series of 'contacts, the taps of said windingsbeing connected to said contacts in a cyclical order of the phases andin the order of their distance from the starting point oi'- theirrespective phase winding, said switching device'comprising means toconnect three successive taps tolthepreceding or phase polygonconnection o! said phase windings.

3. A control device for the control of threephase current comprising anladjustable choke coil to reguiatesaid current, said choke coil havingthree phase windings. each phase winding having amlurality of taps,` -aswitching device having a series of contacts. the tails of said windingsbeing connected tosaid contacts in a cyclical order of the phases and invthe ,orderv of their distances vfrom the starting point ottheirrespective phase,

said vswitching device comprising means to conl nect threesuccessivetaps to a cominonpoint, to

-obtain a connection of said phase windings.

4. 'A controldevice. i'or three-phase current comprising an adjustablechoke ,coil to regulatesaidcurrent, saidchoke coilh'aving three fphasewlndings, eachphase'windin'g having a plurality o! taps, a Supplyconductor i'or each phase and connected to one end of its respectivephase winding, a switchingapparatus comprisingaseriesofcontactathetapsofsaidwindingsbeing connected to said contactsin a cyclical order ci the phases and in the order of their distancefrom the'starting'point of their respective phase winding, saidswitching device comprising means to alternatively connect threesuccessive taps to thev preceding or succeeding phase supply conductorAto obtain a'polygon connection of said phase,windinsadtoconnectthreevetapcto 'a toobtainastar connection oi s. Acontrai device, for the control of a polynosaecs phase currentcomprising, a chokecoil to regu' late said current, said choke coilhaving a plurality of phase windings and each phase winding having aplurality oftaps, asupply conductor for each phase and connected to oneend ofits respective phase winding, a switching i apparatus having aseries oi contacts connected to the taps of said windings in a cyclicalorder of the phases and in the order of the distance of the taps from.the starting point of their respective phase windings, said switchingdevice having a second seriesof contacts connected in a cyclical orderto the phase supply conductors, the numbers ot the contacts of eachseries being equal to the total number of taps, and means tointerconnect the contacts of the two series to`connect three successivetaps of the phase windings to the phase supply conductors to obtain apolygon connection of said phases.

6. A jcontrol device for the control of threephase current comprising,an adjustable choke coil to regulate said current, a4 Supply conductorfor each phase and connected to one end of its respective phase winding,said choke coil having three phase-windings, the starting .pointof eachphase winding being connectedgto one off said phase supply conductors.each phase winding having a plurality of taps, a 'switching devicehaving a series of co tacts, the taps of said windings being connectedvsaid contacts in a cyclical order of the phases and in the order o!their distance from the starting point oi' their respective phasewinding, and a second series of contacts on said switching deviceconnected in cyclical order to said phase supply conductors.and means toconnect three successive taps to. the phase supply conductor so that thetaps are connected to'diii'erent supply conductors as are the startingpoint ot their respective phase-winding.

7. A control device for the control o! three phase current comprising anadjustable -choke coil to regulate said current, said choke coil hav.

ing three phase-windings and each a plurality ot taps, a S'uIplyconductor for' each phase and connected to one end of its respectivephase winding, a switching device having a se' ries o! contacts thenumber ot which equals the total number of taps, said taps beingconnected to said contacts in a cyclical order ofthe phases and theorder of the distance of the taps from the starting point of theirrespective windings, a second series of contacts connected in a cyclicalorder to the phase supply conductors@I third series of electricallyinterconnected contacts, Yand means to alternatively connect threesuccessive contacts of the intermediate series with thethree v phasesupply -conductors to obtain a polygon connection of saidvphase-windings and to connect them with said` third series ,ot'ccntactsto obtain a star connection oi' said phase-windings.

.8. A control device for the control of polyphone current comprising anadjustable choke coil to .regulate said current, said choke-coil havinga plurality of phase windings and each phasewindinghavingaplurality-oftap s,aswitchingde-v vice having three seriesof eachseries having a number o! contacts euualjto number oi taps, oneseriesot contacts beim xediv connected tothe tops. and

io alternatively conn'cctzone each phase with the cocontactolthe secondseries to obtaino Deinen', and with the correspcndingcontactotthethirdseries?.

to obtains star connection.

; s. A conn-o1 device for ure current comprising an adjustable chokecoil to regulate said current -and having a plurality ot phase windings,a supply conductor for each phase and connected to one end of itsrespective phase winding, said phase windings being connected with theirstarting point to one of. said phase supply` conductors,A each phasewinding having a plurality of taps, a switching device having v vummm;plug having pairs of Contact pms the number of which equals the numberoi.' phases three rows of contact sleeves, the vcontact sleeves of theintermediate row being tlxedly connected with the taps oi said windingsin a `cyclical order of the phases and in order ot the distance of thetaps from 'the starting point of their respective phase, one outer rowof contact sleeves being connectedin a cyclical order to the phasesupply conductorsand the other outer row of contact sleeves beingelectrically interconnected, and a movable and so as to be adapted toengage opposing contact sleeves of the middle row and either one of theouter rows toalternatively establish a polygon connection and a starconnection o! the choke-coil windings. f

10. A control device for the control of threephase current comprising achoke-coil having three-phase windings, and a conductor for each phaseand connected to one end of its respective phase winding, each phasewinding having a plurality of taps and being connected with itsstartingpoint to one of said conductors, and a switching device adaptedto provide a plurality of polygon connections of said phases, the numberof which is equal to the number of phases multiplied by the number oftaps less two, and to provide a plurality o! star connections of saidphases, the number oi which is equal to the number of phases multipliedby the number o! taps, minus two, the

transition from successive connections causinga substantially uniformincrease of the current, so that the change of the current through thewhole range oi' control is substantially linear.

